package com.design.behavior.observer.cainiao;

/**
 * @ProjectName: design
 * @Package: com.design.behavior.observer.cainiao
 * @ClassName: Observer
 * @Author: shenaiguo
 * @Description: 创建 Observer 类。
 * @Date: 2020/11/23 0023 20:26
 */
// 第二步
public abstract class Observer {

    protected Subject subject;
    public abstract void update();
}
